Process for separating bismuth from copper.



Vestern and foreign directly applicable for bismuth bearing and lead have been cupeledv or slagged ofi or, in short, from any material showing a 'With sulfur lITJE STATES REFINING 00., OF NEW YORK, N. Y.,

A CQRPOfR-ATION OF NEW JERSEY.

?ROCESS FOR SEPARATING BISll/IUTH FROM COPPER.

No Drawing.

specification of Letters Patent. Application filed September 1'7,

Patented June 2, 1914.. 1910. Serial No. 582,434.

To all whomxit may concern Be it known that I, lVi'LLrAM Then, a citizen-of the United States, and a resident of l-lannnond, in the county of Lake and State of Indiana, have invented certain new and usefulimprovements in Processes for Separating Bismuth from Copper, of which the following is a specification.

The invention relates to a process for the separation of bismuth from copper, Whereby both metals arebrought into condition for further refining to pure metals; .and particularly to a processin which the bismuth is reduced to metal and the copper converted into sulfid (copper matte) With the formation of a suitable slag.

It has for .its object a cheap and effective I method for the separation of bismuth from copper, particularly from oxidized products of these metals. A

The process is particularly adapted for the recovery of the smaller or larger amount of bismuth contained in many grades of .lead bullion, as it affords means to .extract the metal bismuth from. such byproducts obtained in the refining treatment of the bullion. It is further refuse material; byproducts; oXid slugs, such as slags derived from furnace treatment of bismuth bearing copper, or the flue dust of copper converters and furnaces carrying appreciable quantities of bismuth; or from anode slimes from electrolytic lead refining from which the antimony, arsenic in the usual manner as lead antimonite and antnnonate or arsenite and arsenate of lead;

concentration of bismuth in the presence of copper. v

The process is .based upon the fact that sulfur has a much greater affinity for 00p per than for bismuth; and the treatment is such that bismuth is produced in the state of crude metal containing but small amounts of hopper, and the copper in combination as sulfid (copper matte) containing but very small amount of bismutln together with the formation of a readily removable slag. The crude bismuth and the copper matte thus obtained are in excellent oondition'for further treatment and u'efinement. I prefer to cast the crude bismuth into suitable anodes Which are then treated I my co-pendinp' U. S.

' very rhea electrolytically in any suitable manner, as for example by, the apparatus disclosed in application, Serial N o. 20th, 1909. The copper 52am], and Nov.

suliid is treated in the usual manner for the rcurovery of refined copper.

In carrying out my process I proceed as follows: Any product containing principally bismuth and copper is first preferably brought to the oxidized state in any suitable manner, as in that conditifm it can more readily be reduced to the desired fineness by means of crushing apparatus and more intimately mixed with the other ingredients required. As an example of the oXid slag of a heavy metal I may mention the oxid of lead. obtained in oxidizing fusion of lead and known as litharge. A convenient size to which to reduce the oxid slap; is that oh; tamed by screening the crushed material through a screen having four meshes to the linear inch, but a still finer mesh may be used.- The charge is then made up by mixing the crushed material (oxid slag)- inti crushed alkali-sulfur as the sulhd, or preferably 11 alkali. I prefer, however:

mately with finely compound such the sulfate, of a to employ the sulfate such as sodium sulfate (known as salt cake-Na SO,) and to re duce the same to sulfid during the furnace operation of the process by a suitable reducing afrent such as charcoal, coal screenings, coke breeze or other fine carbonaceous matcrial. A sulfate, especially sodium-sulfate, is preferred for the reason that the sulfids of the alkali metals are deliquescent salts and rather dangerous in this connection, causing frequent explosions upon contact with molten masses; also, because sodium sulfid melts more readily than sodium sul fate. This latter-feature is not desirable, as the fusion of the alkali compounds should occur amproxin'iately simultaneously with the reduction, fusion and other'reaetions of the furnace charge. Furthermore, sodium sulfate is a material which may beprocured ply, beinga byproduct of the manufacture of'acid Works. The amount of carbon and salt cake added are largely in. excess of phat would he needed to reduce, lirst--thc sodium sulfate to sodium sulfid, and th n all the oxids to the metallic state.

The sulfur in the salt cake, also. is largely in excesslof the quantity required to convert all the copper into a copper sulfid.

large amounts of silica are deleterious to the process, and the presence of silica in any considerable quantity i not anticipated.

The operations are conducted without difficulty if the amount of the smelting ingre clients added is at least two and one-half times the quantity as indicated by'the theory for reduction and conversion of metals and salts, as aforesaid.

Following are some eitam'plesof the actual amount of carbon and salt cake i prefer to...

add with given percentages of copper contained as oxid, assuming that the bulk of the balance of the oxids consist of bismuth oxid:

Salt cake. 1 Carbon.

I 10% copper l 27.5% of the weight of 16% of the weight of 20% copper "1 ofia b f the weight of l 25% the weight of 30% copper e2 i, %r the weight of l 352;? the weight of Theso prepared charge can be smelted either in a blast furnace or a reverberatory furnace; but I prefer the latter, provided with a cupeling breast that can be scraped down to follow the level of charge. I also prefer to use an oil fired furnace on account of the ease with which necessary changes in temperature are. effected. The material is charged on the hearth of the reverberatory and is smelted down, the batches of mixture being added in easy stages. The heat is adjusted so as to keep the whole fused mass in a perfectly liquid state, care being taken not to let the temperature decrease to a point where chilling under the slag or at the bottom of the furnace can take place. The proper degree of temperature is between 250091 and 3000 F. The operation is finished when the bath ceases to boil or to emit the gases such as G0, etc. There then in the furnace three distinct layers of products, the top layer consisting of soda slags, being amixture of sodium sulfid, sodium sulfate, or caustic soda, etc. Under the slag cover there is a layer of copper sulfid (copper matte), and at the bottom nearly all the bismuth has collected in the metallic state.

.If silver and gold were present in the original material, approximately of the silver and nearly all of the gold is found in similar final" result,-

alumina present in bismuth.

mately 1%, the metal can againbe" o'xid messes the collected'bismuthinetal, and are subsequently recovered in the electrolysis of the Therest'of the silver will be practically all found in the copper matte, very small amountsbeing also held mechamcally in the soda slagsfi' Any arsenic or antimony contained in the original material will be fotmdiifthehbda slags combined soda. Any traces of arsenic or antimony going over to the crude bismuth metal will be entirely eliminated by the electrolytic treatment.

Any tellurium tically all combined withthe; copper, forming a mixture of sulfid-nnd .tellurid of-copper; and, if any leadhas been present orhas been insufliciently removed by the. usual cupeling process of lead and antimony from the original bismuth-copper slag, the same will be found to the extent of approximately 40% of the total amount of lead, in the soda slags, approximately 10% of the total lead in the copper sulfid, and approximately 50% of the total lead in the crude bismuth metal. Lead in the .meta liwill be eliminated by the subsequent electrolytic I treatment of the bismuth. After"thezmelted' mass has ceased boiling, as described "above, it is proper to lower the heat. The slags are then tapped or skimmed over the breast of the furnace into conical pots or molds and are, after cooling, easily separated from any copper matte that may have come over with the slags. After having removed the slag, the heat supply, such as the flame from an oil burner, can be cutout, and theibath allowed to cool for ten minutes to h alf an-ho'ur. The copper matte is th en" tapped or skimmed off as rapidly as possibleinto coriical 'pb'ts" in the same manner as the slag. The heat is new again raised, by setting. into operatic-n the flow of fuel oil through the burner, the remainder of the liquid bath of metal, in the furnace, consisting now chiefly of bismuth with the larger partof the silver and gold that was present in the original Ina-- terial and small percentagesof-impurities such as copper and ileadF Artthis stageit is useful to make a guickcolorimetricltes't for copper on a small 'chilled sample of the metal taken from thefurnace.

If it is found that the copper eliminated to about 1% and no large amounts of silver and gold have been present in the original material treated, the crude bismuth metal can be cast into anodes for subsequent electrolytic refining treat: ment. In case the copper exceeds approirh i lied to oxid slag by contactfwith air, "wh ch I prefer to supply through ironjpipe'sj ,inil serted under the surface of the 'bath, under a pressure of from six to ten pounds to the has been as arsenite or arsenate of soda, or as antimonlte or antnnonate of 7 present ,will befound pracusual manner.

i ,oaaaua a low external heat, the oxidation of the metals PIOClUCIIL most of the heat neces in molten condition.

sary to keep the bath oxid. slag will probut quite rapidly in the latter stages of this The oxids of bismuth and copper are continuously run over the cupel breast of the furnace by scraping the breast down below the level of the furnace bath in the The oxids thus obtained are then again crushed and subjected to the treatment with salt cake and carbon until the reduced metal is sutlicicntly pure for subsequent refining treatment.

if the anode bismuth metal obtained in the first operation contains one or more per cent. of silver and gold, it; is evident that the treatment, as described square inch. The air blowinuis. started at l second oxidation above, would be recommendable for economical reasons; for, by cutting off the oxidizing operation at the point when very little of the bismuth metal remains unoxidized nearly the whole of the'silver and gold can be separated in the shape of a very rich silveugold-bis muth bullion from the bismuth oxid slag, by skimming or tapping this bismuth slag oil to the level of the molten silver and gold metals which do not oxidize at all, or only to a very slight degree. While the subsequent refining treatment would separate the silvcrainl gold, these high values would be tied up longer in process than necessary, and I therefore prefer to liberate them in the furnace operations of my process.

Of course, I do not restrict myself to any proportions of salt cake and carbon nor of sullid, but I have found that an excess of the sodium compound and the carbon is highly beneficial in protectii'ig the metal bath against nictal losses by volatiliration. Thcre 18 no dangcn of any over reduction.

as the whole operation of separating the hismuth into metal and thccopper into matte, with an excess of alkali-sulfur-ccmpmu1d in the slag, will take place without difliculty if conducted in the manner above described. I will further state that l do not restrict myself to the use of sodium sulfid or sulfate, as the otass-iiun compounds would act in a similar manner, but sodium sulfate recommends itself on account of its low price as well as for other reasons, as set forth.

1. The herein disclosed process for the separation of bismuth and copper, which consists in reducing the bismuth copper product, consisting chiefly of bismuth and copper; to a line state, intimately mixing therewith a suitable compound containing; combined sulfur, smelting said mixture to provide crude bismuth and copper matte, and separating the copper matte from the said crude bismuth.

said mixture to provide crude bismuth and copper matte, and separating the copper matte from the said crude bismuth.

;1. lhc herein disclosed process for the separation of bisn'iuth and copper, which consists in oxidizing the bismuth copper product, consisting chiefly of bismuth and copper. reducing the same to a fine state, intimately mixing therewith a mixture of .carbon in excess and sodium sulfate in excess, smelting said l'nixture to provide crude bismuth and copper matte, and separating the copper matte from the sald'crudc bisv m uth.

4.. The herein described process for the separation of bismuth from copper, which consists in'smelting a product containing the same With a suitable compound containing combined sulfur to provide crude bismuth and copper matte, separating the copper matte from said. crudcbismuth, oxidizing said crude bismuth, and then smelting the product with a suitable. sulfur compound.

5. The herein described process for the separation of bismuth consists in :5 citing a product containing the same with a suitable compound. containing combined sulfur to provide bismuth and copper matte, separating the copper matte from said crude bismuth, oxidizing said crude bismuth, and then smelting the same again with a suitable sulfur compound, and finally refining said bismuth and suitably recovering the copper from the matte.

6. The herein described process for the separation of bismuth from copper, which consists in smelting a product containing the some with a suitable sulfur compound. to provide crude bismuth and copper matte, separating the copper matte from said crude bismuth, oxidizing said crude bismuth, but stopping said oxidation at a point Where a small portion of oxidized, removing the said unoxidized portion with any contained unoxidized or slightly oxidized metals, and then smelting said oxidized bisniiuth again with a suitable sulfur compound.

7. The herein described process for the separation of bismuth from copper, which consists in smelting a product containing the same with a suitable sulfur compound by suitably heating until the boiling of the melted mass has ceased, lowering the temperature; and removing the elags, further from copper, which H same I'ElllltlIl-S 1111- Ilm lilld Zllllli ltd casting the same into suitable anodes, and taining the temperature at such a point as finally refining said anodes of bismuth elec' to keep the mass of melted bismuth in a troiyticall'y, liquid state, and suitably removing the 15 The herein described process for the same.

5 separation ofbismuth from copper, which Signed at Hammond, in the county of consists in smelting a product containing the Lake and State of Indiana, this lth day 0"" sa nebwith a suitable 1sullfuilgcolmpounfd by Sept. A. D. 1910.

Suite l heating unti t e oi in o the meltetl mass has ceased, lowering the tem- 1A M THUM' is perature and removing the slags, further Witnessesz" cooling the melted mass and then removing JOHN N. BEGKLAN, the copper matte formed, raising and main- C. H. MOLTERS.

Eagles at this patent m be obtained for five cents each, by addressing the Commissioner of Patents,

' Washington, D. 0. 

